As the reporting season for US banks gets under way this week, consultancy Tricumen has released research showing JP Morgan had the most profitable capital markets business of its peers last year, with pre-tax profits of more than $6bn. JP Morgan and Goldman Sachs are due to report fourth-quarter and full-year earnings on Wednesday.

Tricumen’s estimated figure for JP Morgan was 20% more than its closest rival Citigroup, despite the US bank losing more than $6bn last year from its now-infamous “London Whale” rogue trade.

Barclays, Bank of America Merrill Lynch and Goldman Sachs were the third, fourth and fifth most profitable of the 12 global investment banks Tricumen researched.

It has not disclosed the profit figure for each bank, but Tricumen’s research said the top quartile of firms earned an average pre-tax profit of $5.3bn last year compared with $3.9bn for 2011, while the bottom quartile earned $2.3bn, compared with $2.1bn.

While all the banks included in the research have yet to officially report their fourth-quarter figures, Tricumen has estimated revenues for the last quarter based on public filings, as well as sources from the banks themselves.

Tricumen has sought to normalise the financial performance across the banks, taking into account factors such as different accounting, reporting and regulatory regimes. Seb Walker, a managing director at Tricumen, said: “Comparison between seemingly similar product groups at different banks is fraught with difficulty. On top of this, regulatory hurdles currently demanded by each jurisdiction vary and are, in our opinion, far from being harmonised.

“Our analysis seeks to address some of these issues by normalising banks’ performance parameters. The result is that the true profitability of individual banks’ business lines becomes more transparent and comparable to their peers.”

The research found that JP Morgan had the most profitable primary capital markets business in 2012, with a particular strength in debt capital markets. It was also the second most profitable secondary capital markets business with strength in equity derivatives and fixed income, currencies and commodities products.

Walker said JP Morgan’s top ranking reflected its “broad strength across different business lines”.

Across all banks, Walker said fixed-income divisions had performed most strongly during the year. He said: “Rates and credit both saw the largest improvements in profitability, with strong flow credit, strong short-end rates and inflation revenues being supported with reduced headcount and increased electronic trading.”

In contrast, commodities suffered the most. Walker said: “Our model suggests most of them [banks] are losing money [in commodities].”